There wasn't much in the way of U.S. corporate news on Friday for investors to trade on, according to AP.
So instead, investors chose to worry about Europe.
The 17 countries that use the euro are struggling over what to do if Greece leaves the union, and how much they should do to try to prevent that. Friday produced no definitive developments, which only jangled investors' nerves.
On the New York Stock Exchange, trading was light as investors prepared for the three-day Memorial Day weekend.
Two hours into trading, the Dow Jones industrial average was down 20 points to 12,510. It has been on a steady slide this month, giving up most of the gains it notched in the first quarter. It's almost certain to record its first losing month since September.
The Standard & Poor's 500 index and the Nasdaq composite index flitted between small gains and losses. The S&P 500 was up a point at 1,322. The Nasdaq was down a point at 2,838.
Facebook, marking its one-week anniversary as a public company, fell 3 percent to $31.91 That's still about 16 percent below its initial pricing of $38. Talbots plunged 38 percent after women's apparel company said a deadline expired without a deal to be acquired by Sycamore Partners.
To be sure, Europe's debt problems are nothing new, but Greece's June 17 elections have created a sense of urgency. Investors are watching closely because the country's new leaders will decide whether Greece agrees to the spending cuts that it must swallow if it wants to stay in the euro, or if it goes its own way. Cutting government spending is unpopular in a country where residents have grown used to public-sector largesse.
If Greece left the euro zone, it would revert to its own currency, which would be severely devalued. The country's standard of living would likely worsen dramatically. Greece makes up just 2 percent of the euro zone economy, but its fate would carry ripple effects to other, larger members.